Embedded dual coil fabrication process

ABSTRACT

A read/write head is provided with an embedded planar dual coil write structure. The head includes generally parallel shield, shield/pole, and pole layers. The shield/pole layer abuts a generally coplanar planarization layer in one embodiment. A circuitous recess is defined in the shield/pole and planarization layer, spanning the junction twice and encircling a central hub of adjoining shield/pole and planarization layer material. A write structure is located in the recess, with the shield/pole layer, planarization layer, and embedded write structure forming a substantially flat surface for building the pole layer. The write structure includes first and second substantially co-planar multi-turn flat coils, where turns of the first write coil are interspersed with turns of the second write coil. The first and second write coils reside in the circuitous recess, winding around the central hub. An insulating material separates the first and second coils.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.09/178,377, filed on Oct. 23, 1998, now U.S. Pat. No. 6,191,918.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to read/write heads for reading andwriting digital data to storage media such as magnetic disks. Moreparticularly, the invention concerns a read/write head with a uniqueembedded planar dual coil structure, and a process for manufacturingsuch a head.

2. Description of the Related Art

In this modern information age, there is a tremendous volume ofelectronic data for people and computers to manage. The managementrequirements not only involve transmission, receipt, and processing ofthis information, but storage of the data as well. And, with more datato store, computer users are demanding extremely high capacity digitaldata storage devices. One of the most popular data storage devices isthe magnetic disk drive system, also known as a “hard drive.”

In magnetic disk drives, one of the most critical components is theread/write head. Read/write head characteristics ultimately determinehow densely, quickly, and accurately data can be written to magneticdisk media. As a result, engineers are continually developing better andbetter read/write heads. Two of the chief areas of focus in read/writehead development are data storage density (“areal density”), andread/write speed. In this respect, one improvement in the signal storageability of read/write heads has been the use of two write coils. Thishas been shown to significantly improve the strength and efficiency ofthe data storage.

FIG. 1 shows a partial cross-sectional view of an exemplary dual writecoil read/write sensor 100, with the slider's deposit end (“trailing”)being shown at 103, and the air bearing surface shown 101. The leadingedge (not shown) resides in the direction 105. The sensor 100 is builtupon a slider 102, beginning with an undercoat 104. Upon the undercoat104 lies a first shield 106, known as “S1,” followed by first and secondgap layers 108, 110. Between the gap layers 108, 110 lies a magnetoresistive (“MR”) stripe 107. Upon the gap layer 110 lies a combinationshield/pole 112 known as “S2/P1.” The shield 106, MR stripe 107, andshield/pole 112 cooperatively form a magneto resistive read head 113 ofthe read/write sensor.

A write gap layer 113 is built upon the shield/pole 112, followed by anorganic insulating layer 114. Upon the insulating layer 114 is based afirst write coil 116, which includes a conductive coil embedded in anorganic insulating material that is applied to fill the spacing betweencoil turns and separate the first coil layer from a second coil layer tofollow. The second write coil 118 is layered on top of the first writecoil 116, and similarly includes insulating material applied to fill thespacing between coil turns. A second pole 120, known as “P2,” lies atopthe second write coil 118. After fabricating the second write coil layer118 and its insulation, a plating seed layer (not shown) is deposited,followed by a photo lithography process that defines the shape of thesecond pole 120. The “track width” constitutes the width of the secondpole 120 (in a direction perpendicular to the page depicting FIG. 1) atthe air bearing surface 101. Track width determines the track density onthe disk where bits are written to and read from. The second pole 120 isprotected by an overcoat layer 122. The shield/pole 112, write coils116/118, write gap 113, insulation layer 114, and second pole 120provide the write head 123 aspect of the read/write sensor 100.

One drawback of the sensor 100 is the severe topography created by thesubstantial height of the coil layers 116, 118 and insulation layer 114.This topography is severe because it presents a significant curvaturebeneath the pole 120, instead of a normally flat surface. In a two coillayer structure with organic insulation, the height of this structurecan be as great as ten microns. This great height makes it extremelydifficult to define the second pole 120, especially when a narrow trackwidth is required, for the following reasons. The track widthcorresponds to the dimension of the second pole 120 in a directionperpendicular to the view of FIG. 1 (i.e., into the page). When trackwidth is extremely narrow, there is a high “aspect ratio,” defined asthe ratio of the second pole's width (track width) to its length (fromright to left in FIG. 1). Normally, when track width is larger than thesecond pole's length, no difficulty is presented for creating the pole120 with known photo lithography processes. However, with the dual coilstructure of FIG. 1, the second pole 120 exhibits a high aspect ratio,rendering photo lithography difficult or impossible. Moreover, thisdifficulty increases dramatically with more severe topographies,especially with today's track widths, which are frequently in thesubmicron range. In some cases, this difficulty may be so great thatfabrication of the desired write head may be impossible.

Another drawback of the arrangement 100 is the amount of organicinsulation present in the head. As mentioned above, organic insulationis present around the write coils 116, 118 as well as the insulatinglayer 114. The organic insulating material is typically a polymericmaterial. During operation, the write head is heated from currentpassing the coils. Organic insulation has a lower thermal conductivitythan dielectric materials in the head, such as silicon-oxygen andaluminum-oxygen based materials. This low thermal conductivity impedesheat dissipation, causing the temperature of the write head to increase.Increased operating temperatures have various undesirable effects, suchas decreasing head life. Furthermore, due to the organic insulation'srelatively high thermal expansion coefficient, the organic insulationresponds to the heat by expanding more than the nearby layers of thehead. This expansion may cause portions of the head to protrude from thenormally flat air bearing surface 101. With the head now enlarged by theprotrusions, the head's effective flying height is smaller, and there isa greater danger of the head contacting the storage surface. Suchcontact may cause further heating of the head, or a disastrous headcrash in extreme cases. To avoid head/disk contact, a higher flyingheight is necessary between the head and disk surface. However, with ahigher flying height, signals stored by the write head are weaker, andrequire more surface area to safely store adjacent signals that aredistinguishable from each other. Thus, the protrusion due to thepresence of the organic insulation ultimately lowers the areal densityof stored signals, diminishing the disk drive's storage capability.

In view of the foregoing, then, the structure and fabrication of knowndual coil write heads present a number of unsolved problems.

SUMMARY OF THE INVENTION

Broadly, the present invention concerns an improved read/write head,including an embedded planar dual coil write structure. The headincludes a shield layer, a shield/pole layer substantially parallel tothe shield layer, and a pole layer substantially parallel to the shieldand shield/pole layers. In one embodiment, one edge of the generallyplanar shield/pole layer reaches an air bearing surface of the head, andthe opposite edge abuts a substantially coplanar planarization material.A circuitous channel spans the junction between the shield/pole and theplanarization material twice, encircling a central “hub” (or “island”)of shield/pole and bordering planarization material. A write structureis located in this channel, called a “recess”, with the shield/pole andits portion of the embedded write structure covered by the pole layer.

The write structure includes first and second substantially coplanarmulti-turn flat coils, where turns of the first write coil areinterspersed with turns of the second write coil. Coil turns aresubstantially parallel to the shield/pole layer. The coils reside in therecess defined in the shield/pole layer and the planarization materialand wind around the central hub. A dielectric material is present toseparate the first coil from the second coil.

Accordingly, one aspect of the invention is an apparatus, such as aread/write head with an embedded planar coil write structure, or a diskdrive system incorporating such a head. A different aspect is a methodof fabricating the read/write head of the invention.

The invention affords its users with a number of distinct advantages.Unlike prior configurations, the invention provides a manageabletopography for constructing a second pole layer in a dual coilread/write head. As a result, even with a dual coil construction, theinvention may be used to construct read/write heads that defineminuscule track widths of previously impossible dimension. Anotheradvantage is that the invention's read/write head includes significantlyless organic insulation material, since the two coils are integrated.This helps avoid undesirable heating and associated thermal expansion ofthe head. As a result, flying height can be lowered, increasing theareal density of stored signals, and proportionally decreasing theoverall size of the storage media. The invention also provides a numberof other advantages and benefits, which should be apparent from thefollowing description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional diagram of a known dual coilread/write head.

FIG. 2 is a perspective view diagram of a slider incorporating theread/write head of the invention.

FIG. 3 is a partial cross-sectional side view of the read/write head ofthe invention.

FIG. 3A is a cut-away top view of the read/write head of the inventionwith organic insulation, write gap, P2, and protective overlayer removedto feature the embedded planar dual coil structure of the invention.

FIG. 4 is a block diagram of a disk drive system utilizing theread/write head of the invention.

FIG. 5 is a flowchart of an operational sequence for fabricating anembedded planar dual write coil structure in accordance with theinvention.

FIGS. 6A-6L are partial cross-sectional side views of a read/write headin various stages of fabrication according to the invention.

FIG. 7 is a diagram showing etch rates of NiFe, alumina, and photoresist as a function of milling angle.

DETAILED DESCRIPTION

The nature, objectives, and advantages of the invention will become moreapparent to those skilled in the art after considering the followingdetailed description in connection with the accompanying drawings. Asmentioned above, the invention concerns a read/write head with a uniqueembedded planar dual coil structure, and a process for manufacturingsuch a head. As described below, a different aspect of the invention isa disk drive system incorporating a read/write head with an embeddeddual coil write structure.

HARDWARE COMPONENTS & INTERCONNECTIONS

Slider

FIG. 2 depicts a read/write head 200 in perspective view to help explainthe invention in context. The head 200 includes an air bearing surface(“ABS”) 202 which normally glides over a storage disk (not shown)separated by a thin cushion of air called an “air bearing” (not shown).In the illustrated example, the head 200 moves in a direction 205relative to the storage medium. The ABS 202 is raised with respect to asurrounding surface 204 that is recessed by a process such as etching,ion milling, etc.

The head 200 has a leading edge 206 and a trailing edge 208. Near thetrailing edge 208 lies a read/write head 210, which lies flush with theABS 202 and contains circuit components that actually perform the readand write operations. These circuit components are deposited onto thetrailing edge 208 of the head 200, which may also be called the “depositend.” As explained in greater detail below, the read/write head 210includes a shield 220, a shield/pole 222, and a pole 224, each too smallto be separately visible in FIG. 2. The shield 220 may also be called“S1,” the shield/pole 222 may be referred to as “S2/P1,” and the pole224 may be referenced as “P2.”

Read/Write Head Structure

FIG. 3 shows a partial cross-sectional view of the read/write head 210,which was generally described above with reference to FIG. 2. Referringto FIGS. 2-3, the read/write head 210 is built upon the trailing edge208 of the head 200. More particularly, the read/write head 210 is builtupon material of a slider 302, which may also be referred to as asubstrate. The substrate may comprise silicon, a semiconductor, oranother material with similar properties. As a specific example, thesubstrate may be a combination of elements such as aluminum, oxygen,titanium, and carbon. Above the slider 302 lies an undercoat layer 304,followed by the shield 220 (S1). The shield 220 comprises a magneticmaterial such as a nickel-iron alloy, nickel-iron-cobalt alloy, Sendust,a cobalt-zirconium-niobium alloy, etc. Atop the shield 220 lies a firstgap layer 306, a second gap layer 310, and an MR stripe 308 interposedbetween the gap layers 306/310 proximate to the ABS 202. The gap layers306/310 may comprise electrical insulators, for instance.

In the illustrated example, the gap 310 is covered by the shield/pole222 (S2/P1), and also by a planarization layer 312 that abuts theshield/pole 222 at a junction 395. The shield/pole 222 and planarizationlayer 312 together form an intermediate layer 380 between the shield 220and pole 224. In the illustrated example, the planarization layer 312comprises an electrical insulator such as alumina, anotheraluminum-oxygen combination, a silicon-oxygen combination, or anothermaterial with suitable properties such as electrical insulation, asimilar expansion coefficient as the shield 222, similar wearcharacteristics (e.g. lapping) as the shield 222, etc. The shield 222comprises a magnetic material such as a nickel-iron alloy,nickel-iron-cobalt alloy, Sendust, cobalt-zirconium-niobium alloy, etc.In the alternative embodiment, the planarization layer 312 may comprisea conductive non-magnetic material. Although using an electricalinsulator or conductive non-magnetic material as the planarization layer312 offers the advantage of low inductance, the planarization layer 312may comprise a magnetic material and may even be indistinguishable fromthe shield/pole 312; in this embodiment, the intermediate layer 380 andthe shield/pole (S2/P1) are the same, and the shield/pole occupies bothregions 222 and 312. For explanatory purposes, the present discussionillustrates the embodiment where the shield/pole 222 and planarizationlayer 312 are separate materials that meet at the junction 395.

The intermediate layer 380 exhibits a contiguous recess 314 defined inthe shield/pole 222 and the layer 312 and spanning the junction betweenthese parts. The recess 314 has the shape of a circuitous channel thatspans the junction 395 twice, encircling a central “hub” 390 ofshield/pole and adjacent planarization material. The recess 314 is“circuitous” in that it defines a continuous path, with no end orbeginning as it travels around the central hub 390. The recess 314 is acontiguous channel traveling around the hub 390, but due to thecross-sectioned view of FIG. 3 appears as two separate recessed areas314 a-314 b. As one example, the recess 314 may exhibit a ring(“annular”) shape, with the hub 390 as its center. The recess 314 may,however, exhibit more elliptical, rectangular, or other features,depending upon the shape of the embedded planar dual coil writestructure 315 to reside therein.

More specifically, the planar dual coil write structure 315 includes aninsulating layer 316, comprising alumina or another material withsimilar properties of electrical insulation. Atop the layer 316 reside apair of write coils, made of a conductive material such as copper oranother material with similar properties. The overall structure of eachwrite coil is generally flat, where each coil starts from a centralpoint and proceeds outward. As one example, the coils may be shapedspirally, like a burner coil of an electric stove. Alternatively, moreelliptical, rectangular, or other shapes may be used. As both coilsstart and proceed outward together, the turns of one coil areinterspersed with those of the other. One coil includes turns 320,whereas the other coil includes alternating turns 322 interspersed withthe turns 320. The individual turns are tapered. In the case of theturns 320, for instance, they are tapered to provide a wider dimensiontoward the substrate 302. The turns 322 have an opposite taper,providing a smaller dimension toward the substrate 302. In theillustrated example, each tapered coil turn exhibits a generallytrapezoidal cross section. The turns of one coil are electricallyseparated from the other coil's turns by a layer 318, which comprises aninsulating material such as a dielectric substance. FIG. 3A shows thedual coil structure from a top view, with all layers (i.e., 324, 326,224, 350) overlying the intermediate layer 380 and coils 320/322removed, to more thoroughly illustrate the coil structure.

Over the shield/pole 222, dual coil write structure 315, andplanarization layer 312 lies an insulating layer 324, which comprises aninsulating material such as organic polymer, dielectric, analuminum-oxygen combination, a silicon-oxygen combination, etc. Abovethe layer 324 is a write gap layer 326, comprising a non-magnetic,conductive or non-conductive material such as an aluminum-oxygencombination. The last magnetic component of the read/write head 210 isthe pole 224, which overlies the write gap layer 326. The pole 224comprises a magnetic material of similar composition as the shield 220and shield/pole 222. The pole 224 is covered by a protective overlayer350, made of alumina or another material seeming to encapsulate the head200 and provide sufficient chemical and mechanical protection. Aprotective over layer 309 may also be applied at the air bearingsurface, to guard various layers of the read/write head that wouldotherwise be exposed, such as layers 304, 220, 306, 308, 310, 222, 326,and 224. The layer 309 may comprise carbon or another layer providingsufficient chemical and mechanical protection to the read/write head210.

Disk Drive System

FIG. 4 shows a different aspect of the invention, comprising a diskdrive system 400 incorporating a read/write head with an embedded planardual coil write structure. The disk drive system 400 includes at leastone rotatable magnetic disk 412 supported on a spindle 414 and rotatedby a disk drive motor 418. The magnetic recording media on each disk isin the form of an annual pattern of concentric data tracks (not shown)on the disk 412.

At least one slider 413 is positioned near the disk 412, each slider 413supporting one or more magnetic read/write heads 421, where the head 421incorporates the read/write head of the present invention. As the disksrotate, the slider 413 is moved radially in and out over the disksurface 422 so that the heads 421 may access different portions of thedisk where desired data is recorded.

Each slider 413 is attached to an actuator arm 419 by means of asuspension 415. The suspension 415 provides a slight spring force thatbiases the slider 413 against the disk surface 422. Each actuator arm419 is attached to an actuator mechanism 427. The actuator mechanism419, for example, may be a voice coil motor (“VCM”) comprising a coilmovable within a fixed magnetic field, where the direction and speed ofthe coil movements are controlled by the motor current signals suppliedby the controller 429.

During operation of the disk drive system 400, the rotation of the disk412 generates an air bearing between the slider 413 and the disk surface422, which exerts an upward force or “lift” on the slider. The surfaceof the slider 413 that includes the head 421 and faces the surface 422is referred to as an air bearing surface (“ABS”). The air bearingcounterbalances the slight spring force of the suspension 415 andsupports the slider 413 off and slightly above the disk surface by asmall, substantially constant spacing during normal operation.

In operation, the various components of the disk storage system arecontrolled by control signals generated by a control unit 429. Thesecontrol signals include, for example, access control signals andinternal clock signals. As an example, the control unit 429 may includevarious logic circuits, storage, and a microprocessor. The control unit429 generates control signals to control various system operations suchas drive motor control signals on line 423 and head position and seekcontrol signals on a line 428. The control signals on the line 428provide the desired current profiles to optimally move and position theslider 413 to the desired data track on the disk 412. Read and writesignals are communicated to and from read/write heads 421 by means of arecording channel 425.

The above description of the magnetic disk storage system andaccompanying illustration of FIG. 4 are for representation purposesonly. Ordinarily skilled artisans (having the benefit of thisdisclosure) should recognize various additions or other changes that maybe made to the system 400 without departing from the invention.Moreover, disk storage systems may contain a large number of disks andactuators, and each actuator may support a number of sliders.

Fabrication Process

In addition to the various hardware embodiments described above, adifferent aspect of the invention concerns a process for fabricating aread/write head with a unique embedded planar dual coil structure.

Introduction

FIG. 5 shows a sequence 500 to illustrate one example of the processaspect of the present invention. The sequence 500 describes theconstruction of a read/write head incorporating the embedded planar dualwrite coil structure of the invention. For ease of explanation, butwithout any limitation intended thereby, the example of FIG. 5 isdescribed in the context of the head shown in FIGS. 3-3A, and describedabove.

Building Initial Structure

After the process 500 is initiated in step 502, the read/write head isbuilt until the shield/pole 222 is completed, as shown by step 504. Thisinvolves fabrication of the slider 302, overlayer 304, shield 220, gaplayers 306/310, and MR stripe 308. As an example, these operations maybe performed using techniques well known to ordinarily skilled artisansin this art. Upon the gap layer 310, the shield/pole 222 andplanarization layer 312 are constructed. These components havesubstantially the same thickness, and abut each other at a commonjunction 395.

Defining Recess

Having completed the read/write head up to the level of the intermediatelayer 380, step 506 is then performed to define the 314 recess spanningthe shield/pole 222 and the adjacent planarization layer 312 toaccommodate the write coils. Creation of the recess 314 begins with theread/write head in the condition shown in FIG. 6A. At this point, theshield/pole 602 and adjacent layer 604 do not yet define any recesses.These layers meet at a junction 395, and provide a continuous,substantially flat surface 605. The layers 602 and 604 have a commonlower surface 690 abutting the gap layer 310, which is not shown inFIGS. 6A-6L for ease of illustration.

The recess 314 (as shown by areas 314 a-314 b) is defined using a photolithography process, which begins in FIG. 6B. Namely, photo resist masks606 a-606 b are applied to define an opening 607 (areas 607 a-607 b)defining the desired location of the recess 314 (areas 314 a-314 b). Thelocation of the mask 606 b determines the position of the hub 390 (FIG.3). Next, an ion milling process is applied to erode the shield/pole 602and the layer 604 at substantially the same rate. In this presentexample, where the shield/pole 602 is made of a nickel-iron alloy andthe layer 604 is made of alumina, a special technique is used to erodethese materials at the same rate. Namely, this technique involvesperforming ion milling with the wafer tilted at about fifty to sixtydegrees (“milling angle”) using ion beam voltage of about 650 volts. Theinventors have discovered that this technique mills the shield/pole 604and layer 604 at about the same rate. FIG. 7 shows the milling rate ofnickel-iron (NiFe), alumina, and photo resist as a function of millingangle at 650 V beam voltage. The milling rates of nickel-iron andalumina are essentially equal at milling angles of about fifty to sixtydegrees.

After the shield/pole 602 and overlayer 604 are milled sufficiently tothe desired depth, and the photo resist masks 606 a-606 b removed, theread/write head appears as shown in FIG. 6C. Namely, recessed areas 314a-314 b are now provided in the opening 607 left by the masks 606 a-606b. Removal of the photo resist masks 606 a-606 b may be achieved byapplying a solvent, or another known technique. The milled shield/pole308 and milled planarization layer 610 are shown in FIG. 6C.

Constructing Write Structure—Coating Recess with Insulation

With construction of the read/write head advanced to the state shown inFIG. 6C, construction of the write structure occurs in step 508. Asshown below, the write structure includes a pair of substantially planarcoils, and these coils are embedded in the recessed areas 314 a-314 bcreated in the shield/pole 608 and planarization layer 610. In step 510,the recessed areas 314 a-314 b are coated with a layer 316 of alumina oranother insulating material of similar properties. As an example, thelayer 316 may have a thickness of about 2000 Angstroms. This isperformed to electrically insulate the shield/pole 608 from the writecoils, and may be accomplished using a suitable technique such as vacuumdeposition. More particularly, step 510 may employ sputteringdeposition. The completed insulation layer 316 is shown in FIG. 6D.

Constructing Write Structure—First Coil

After step 510, the first coil is applied in step 511, this stepinvolving a number of sub-steps. First, as shown in FIG. 6E, aconductive seed layer 614 is applied by an appropriate technique, suchas sputtering deposition. As an example, the seed layer 614 may comprisea chromium/copper layer (CrCu) of about 800 Angstroms. The seed layer614 provides a surface conducive to the addition of conductive coilmaterial, as discussed below.

Next, a “cast” is made in the proper shape to create coils of the firstwrite coil. A completed cast 616 is shown in FIG. 6F, and may beconstructed by a suitable photo lithography process. For example, aresist material, such as a photosensitive polymer, may be applied usinga spin coat technique. Then, a mask is applied for exposure and theunwanted resist material is dissolved using a developing chemical. Thisforms a cast 616, which is made of the resist material. The cast 616includes a number of openings 618, which define the shape of the firstwrite coil, as discussed below.

In the illustrated embodiment, the openings 618 are “tapered,” beingwider at the bottom and narrower at the top to define a shape oftrapezoidal cross-section. This is useful, as discussed below, becausethe resultant first write coil will provide a cast for creating a secondwrite coil of complementary shape. This tapered shape is achieved byusing a negative tone resist.

With the cast 616 defined, the coil material is applied to the openings618. As an example, this material may be copper, which is applied byelectroplating. After applying the coil material, the resist cast 616 isstripped using an organic solvent such as acetone or N-methylpyrrolidoneor another dissolving chemical; also the seed layer 614 is removed usinga dry etch technique such as ion milling. This completes the first coiland step 511. As shown in FIG. 6G, the coil includes multiple turns 320,the shape of which has been defined by the now-absent resist openings618.

Constructing Write Structure—Encapsulating

After the first write coil is constructed in step 511, the dielectriclayer 318 is applied over the first write coil in step 512. Thisencapsulates the turns, insulating them from the second write coil, tobe applied next. Step 512 may be performed by applying a dielectricmaterial by a suitable vacuum deposition technique, such as chemicalvapor deposition, sputtering, plasma deposition, or enhanced chemicalvapor deposition. As a more specific example, the dielectric layer 318may comprise 5000 Angstroms of chemical vapor deposition (“CVD”) orplasma enhanced chemical vapor deposition (“PECVD”). The tapered shapeof the write coil 320 improves the coverage of the dielectric layer 318over the coil turns.

FIG. 6H depicts the read/write head with encapsulated write coils. Thesurface of the dielectric layer 318 defines a number of recesses 624,shaped to provide a cast for construction of the second write coil.

Constructing Write Structure—Second Coil

After the insulation is applied in step 512, construction of the secondwrite coil begins. Referring to FIG. 6I, a seed layer (not shown) isfirst applied to the dielectric layer 318 by an appropriate technique,such as sputtering deposition. As an example, the seed layer maycomprise a chromium/copper layer (CrCu). The seed layer provides asurface conducive to the addition of conductive coil material, asdiscussed below.

Next, a suitable photo lithography process is performed to construct aresist mask 629 covering the read/write head, except for the recessedareas 314 a-314 b. The resist mask 629 may additionally cover a smallportion of the outer ends of the recessed areas 314 a-314 b (as shown),in order to avoid the deposition of coil material in those areas. Theresist mask 629 is constructed by applying a resist material (notshown), such as a photosensitive polymer, using a spin coat technique.Then, another mask (not shown) is applied and the exposed resistmaterial is dissolved using a developing chemical. This forms the resistmask 629, which provides openings 625 a-625 b.

With the resist mask 629 in place as shown in FIG. 6I, a coil materialis applied. Application of the coil material is limited to area left bythe openings 625 a-625 b. As an example, the coil material may becopper, which is applied by electroplating. After applying the coilmaterial, the resist mask 629 is stripped using an organic solvent suchas acetone or N-methylpyrrolidone or another dissolving chemical; also,the seed layer is removed using a dry etch technique such as ionmilling. This completes step 513, leaving the read/write head in thecondition shown by FIG. 6J. Although the material of the second coil isin place, some finishing work still remains, as explained below.

Constructing Write Structure—Finishing

After step 513, a finishing step 514 is performed. First, the read/writehead is processed with chemical-mechanical polishing to wear away theexcess copper material 626 protruding beyond the recesses 614 a-614 b.More particularly, polishing may be performed using a slurry of quartzparticles suspended in persulfate ammonium potassium aqueous solution,with the persulfate concentration at about 3%. After polishing, the seedlayer is removed by a suitable technique, with one example being a dryetch technique such as ion milling. With the seed layer gone, materialof the dielectric layer 318 protruding beyond the recessed areas 314a-314 b is removed by a process such as a wet etch technique.

The result of the finishing step 514 is the read/write head as shown inFIG. 6K. At this point in the fabrication process, the first coil 320and second coil 322 are in place. Turns of the first coil 320 alternatewith turns of the second coil 322. The turns of each coil are insulatedfrom the other coil by the insulating layer 318. All coil turns exhibita tapered shape, where turns 320 of the first coil are wider toward theunderlying shield/pole 608, and turns 322 of the second coil arenarrower toward the shield/pole 608. Both write coils are completelyembedded in the shield/pole 608 and the planarization layer 610, withthese structures cooperatively providing a flat surface 670 for buildingthe pole 224, as discussed below.

Completing the Read/Write Head

After step 514, the write structure is complete, ending step 508. Next,step 516 is performed to complete the read/write head. First, theinsulating layer 324 is applied over the recess 314 containing the writecoils as shown in FIG. 6L. Application of the insulation layer 324 maybe achieved using photo lithography, the details of which have beenexplained above. The insulating layer 324 comprises an organic material,such as a polymer. After placing the insulation layer 324, it may becured by baking.

Upon the insulating layer 324 is placed a write gap 326, as shown inFIG. 6L. The write gap may be layered using vacuum deposition, forexample. Placement of the write gap 326, and the ensuing pole 224 andprotective overcoat 350 (not shown in FIG. 6L) may be achieved by wellknown techniques. Known methods may also be used to connect the writecoils 320, 322 to appropriate conductive leads.

Other Embodiments

While the foregoing disclosure shows a number of illustrativeembodiments of the invention, it will be apparent to those skilled inthe art that various changes and modifications can be made hereinwithout departing from the scope of the invention as defined by theappended claims. Furthermore, although elements of the invention may bedescribed or claimed in the singular, the plural is contemplated unlesslimitation to the singular is explicitly stated.

What is claimed is:
 1. A process for making a magnetic write headcomprising: applying a substantially planar shield layer to a structureincluding a slider; applying one or more gap layers on top of the shieldlayer; applying a substantially planar intermediate layer over the gaplayers, the intermediate layer being substantially parallel to theshield layer, and including a magnetic shield/pole material and theintermediate layer having a first surface opposite the shield layer;defining a circuitous recess in the first surface, the recesssurrounding a hub of unrecessed intermediate layer material; andconstructing a write structure including first and second substantiallyco-planar multi-turn flat write coils, where turns of the first writecoil are interspersed with turns of the second write coil, and allportions of both first and second write coils reside in the circuitousrecess and wind around the hub.
 2. The process of claim 1, the applyingof the substantially planar intermediate layer comprising application ofa shield/pole layer abutting a substantially coplanar planarizationlayer at a junction, the shield/pole layer and planarization layercooperatively forming the first surface.
 3. The process of claim 2, thedefining of the circuitous recess defining the recess to span thejunction such that the hub includes a portion of the junction.
 4. Theprocess of claim 2, the application of the intermediate layercomprising: applying a layer of NiFe to form the shield/pole; andapplying a layer of alumina to form the planarization layer.
 5. Theprocess of claim 4, the defining of the recess comprising: coating theintermediate layer with a photo resist mask having an opening over adesired extent of the recess; applying an ion beam to perform ionmilling of the photo resist coated intermediate layer while theintermediate layer forms an angle between fifty and sixty degrees withrespect to the ion beam.
 6. The process of claim 2, the defining of therecess comprising: etching the shield/pole layer and planarization layerat substantially uniform rates.
 7. The process of claim 6, the etchingcomprising ion milling.
 8. The process of claim 1, the constructing ofthe write structure including constructing of the first write coil,comprising: using photo lithography to define a first tapered coil castin the recess, the first coil cast having a shape complementary to adesired shape of the first write coil; depositing a conductive materialin the cast to form the first write coil in the desired shape.
 9. Theprocess of claim 8, the first write coil having an exposed surface, theconstructing of the write structure further comprising: applying aninsulating layer to the exposed surface of the first write coil, theinsulating layer conforming to the first write coil.
 10. The process ofclaim 9, the insulating layer having an outer surface defining a secondtapered coil cast having a shape complementary to a desired shape of thesecond write coil, the constructing of the write structure furthercomprising: depositing a conductive material in the second cast to formthe second write coil in the desired shape.
 11. The process of claim 10,further comprising: applying a layer of insulation overlying the writestructure.
 12. The process of claim 7, further comprising applyingchemical-mechanical polishing to the write structure.
 13. The process ofclaim 12, the application of the chemical-mechanical polishing using aslurry including quartz particles suspended in persulfate ammoniumpotassium aqueous solution.
 14. The process of claim 1, the constructingof the write structure comprising: applying an insulation layer tosurfaces of the shield/pole and planarization layer that define therecess; applying a seed layer to the insulation layer; using photolithography to define a first tapered coil cast in the recess, the firstcoil cast having a shape complementary to a desired shape of the firstwrite coil; depositing a conductive material in the cast to form thefirst write coil in the desired shape, the first write coil having anexposed surface; applying an insulating layer to the exposed surface ofthe first write coil, the insulating layer conforming to the first writecoil and having an outer surface defining a second tapered coil casthaving a shape complementary to a desired shape of the second writecoil; depositing a conductive material in the second cast to form thesecond write coil in the desired shape; and applying chemical-mechanicalpolishing to the write structure.
 15. The process of step 14, furthercomprising: applying a layer of insulation overlying the writestructure, and applying a substantially flat pole layer over theinsulation overlying the write structure.